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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MG Y Type - COIL TESTING DATA

I have tested the coil off a YA or YB with an ohmeter with the result as far as I can make out that the primary circuit is about 3.5 ohms and the secondary (HT) circuit measures about 5000 ohms.

Does anyone know if these results are correct for the Y-Type coils or is it likely to be scrap? I understand that the readings for a modern car arew likely to be much higher, but does this apply to those designed 60 odd years ago?

I would appreciate any ideas on this because I intend to put it on E-Bay shortly if it is O.K.

Thanks

Clive Evrall
J.C. Evrall

Hi Clive

I just tested the "old faithful" that is on my engine test rig and that had Primary circuit of 4.7 ohm and Secondary circuit of 5370 ohm.

I am a little skeptical about the 4.7 ohm reading as I know most modern coils run either 3.5 or 1.5 ohm (the latter usually having an external ballast resistor) so I would say yours is in the ball park.

Sorry for any delay in getting back to you.

Paul
Paul Barrow

Many thanks Paul

I wasn't at all sure but your reply gives me a great deal more confidence. I had googled "how to test a coil" and the figures given for modern coils indicate a much higher secondary coil resistance and as you say a lower resistance for those with a ballast resistance. There are a few articles on this subject, most of which go over my head!

Your help is much appreciated

Clive
J.C. Evrall

You are welcome Clive. Your coil will work OK with T Types and also witht he Wolsely 4/44 and indeed many cars of the same period using the XPAG so do not limit your appeal tojust the MG Y Type in your eBay description.

A good coil will promote good starting performance and avoid the sort of poor starting that plaqued cars in the 1960s. Of course a good battery, good grounding and clean terminals all help too. Amazingly of all my cars though, stored in exactly the same garage, the Y is the easiest to start after prolonged idleness - such great cars.

Paul
Paul Barrow

Thanks again Paul. I have been wondering why the design for modern coils differs so much in specification so much from classsic ones. The only thoughts that I can come up with was that perhaps there was a shortage of copper in the mid 1940s or maybe todays higher compression engines need more of s spark, hence the higher voltage?

How is the T-Type getting on by the way?

Clive
J.C. Evrall

Sorry Paul, I meant the YT of course. Penalty of advancing years!

Clive
J.C. Evrall

This thread was discussed between 28/09/2010 and 04/10/2010

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